Sometimes I need to configure fcontexts for *wp-content/cache* as writable by the web server, which should apply for existing files/directories, and for those which will be created in the future.
I've configured such thing a couple of times, with CentOS release 6.9 (Final) and CentOS Linux 7 and there was no problem with it.

But now I have stuck witch a situation that was never been an issue before.

Well, I was hoping at least to get something with restorecon command, but the file and the directory are created with httpd_sys_content_t , not httpd_sys_rw_content_t, and restorecon command actually does not changes that: